Silver salmonOncorhynchuskisutch
(Walbaum)
1792

COHO SALMON

[Jordan and Evermann, 1896-1900, p. 480.]

Description—

The silver salmon resembles a rather stout Atlantic salmon closely in its general shape, also in the relative size and position
of its fins, and in their shapes. But a safe morphological criterion for distinguishing the one from the other is that the
silver always has at least 12 rays in its anal fin, and some of them have as many as 17, whereas most of the Atlantic salmons
have only 8 or 9 anal rays, and never more than 10. The color is a help also, in this connection, for while a silver is silvery
down its sides, like an Atlantic salmon, it is more closely sprinkled with small black spots along its back and on the upper
part of its tail fin than is an Atlantic salmon. These spots, too, are always roundish or oval in a silver, never in the form
of crosses. On the other hand, the black spots are much smaller and much less conspicuous on a silver salmon than on a humpback,
and the lower half of the tail fin, which is as conspicuously spotted as the upper half on a humpback, usually has no spots
on a silver salmon.

Size—

Up to 3 feet in length.

General range, habits, and occurrence in the Gulf of Maine—

The native range of the silver salmon is from northern California to northwestern Alaska, where it is an important food fish,
and where anglers take many of them, both by trolling and by fly fishing. Like other Pacific salmons, it runs up into fresh
streams to spawn, dying thereafter. Most of the young remain about one year in fresh water, but a few do not move out to sea
until they are in their third year. Most of them return to fresh water at the end of the third summer at sea, a few, however,
by the end of the second summer in salt water, a few others not until the fourth summer.

Our only reason for mentioning the silver salmon is that a plant of its fry and fingerlings that was made in the Duck Trap
stream, tributary to the western side of Penobscot Bay, near Lincolnville, Maine, resulted in the return of 150 mature fish
to Duck Trap stream in 1944, and perhaps of more of them. But nothing more was heard of them thereafter, and no returns have
been reported up to this writing (Nov. 1, 1951) from other plants that were made in Maine waters[2] in 1948.